Exhaust system for a motorcycle



FIG. 1 is a right view of an exhaust system for a motorcycle, showing my new design;

FIG. 2 is an enlarged right view thereof;

FIG. 3 is an enlarged top view thereof;

FIG. 4 is an enlarged front view thereof;

FIG. 5 is an enlarged left view thereof;

FIG. 6 is an enlarged rear view thereof; and,

FIG. 7 is an enlarged bottom view thereof.

The broken line showing of environment is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a exhaust system for a motorcycle, as shown and described. 